APPLIED CHEMISTRY TODAY
Year:2024 | Volume:19 | Issue:72|Papers Count:18

In this research, reduced graphene oxide-silver nanocomposites (RGO-Ag NCs) was synthesized by a green and easy method. In this direction, jujube extract was used as a reducing and stabilizer of nanocomposites in an aqueous environment without chemical reducing and special complexity. Reduced graphene oxide was used as a support because of its high surface area, chemical stability, and good conductivity. This RGO-Ag NCs is characterized by conventional methods such as Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction Pattern (XRD), Scanning Electron Microscope (FE-SEM), X-ray Energy Diffraction Spectroscopy (EDS), Visible-Ultraviolet spectroscopy (UV-Vis) and Raman spectroscopy. The RGO-Ag NCs was used as a visible light plasmonic photocatalyst in the degradation of Rhodamine B dye in aqueous solution. Also, factors affecting photocatalytic degradation such as Rhodamine B dye concentration, amount of RGO-Ag NCs and initial pH of the solution were investigated. The results showed that the degradation rate of 100.0 mL of 1 ppm rhodamine B solution by 0.020 g of RGO-Ag NCs at pH = 6 within 45 minutes under visible light irradiation was 91.34%. It was also found that the rate of dye degradation follows pseudo-first-order.

In this research, a new and environmentally friendly chemical sensor was introduced using Bromopyrogallol red (BPR) to determine trace amounts of aluminum and fluoride ions in dimethyl sulfoxide/water (5.5, v/v) solvent. The results showed that the color of BPR changes from red to violet under the influence of visible light in the presence of aluminum ions. This chemical sensor can selectively detect aluminum with a detection limit 2.21×10-7 and quantitation limit 7.37×10-7 mol L−1. Upon addition of aluminum ion, the absorbance signal of [Al-BPR] increased linearly in the concentration range of 1.60×10−6 - 8.06×10−5 mol L−1. In addition, [Al–BPR] complex can be used for the determination of F-. The signal of [Al-BPR] upon addition of F- decreased linearly in the concentration range of 4.0×10-5 - 8.80×10-4 -. The relative standard deviation (RSD) for 5 times of measurement (n=5) in two concentrations of 1.87×10-5 and 3.07×10-5 mol L−1 of aluminum are 2.9% and 2.1% respectively. To determine the stoichiometry of the reaction between BPR receptor and aluminum ion, the molar ratio method was used. According to the experiments, this ratio was determined to be 1:1. BPR can also be used to detect aluminum ions in different water samples with high recovery percentage.

In this research, the magnetoelectropolishing method was used to prepare the surface of 304SS steel. The electropolishing process has been carried out in different modes including without magnetic field, Lorentzian force perpendicular to the surface outward, Lorentzian force parallel to the surface and Lorentzian force perpendicular to the surface inward. The methods of scanning electron microscopy, atomic force microscopy, potentiodynamic polarization test and electrochemical impedance were used to check the surface morphology, elemental composition, surface roughness and corrosion resistance of the samples in each state. According to the results, the direction of the magnetic field and in fact the direction of the hydrodynamic flow resulting from the Lorentzian force has a decisive contribution to the surface properties of the sample such as morphology, roughness and corrosion resistance. The best results occurred when the Lorentzian force was parallel to the surface. In this case, the amount of iron on the surface reaches 69.94%, which is the lowest amount compared to other cases of magnetic field placement, and the amount of iron in the case where the magnetic field does not enter the system is 73.52%, which indicates an improvement in corrosion resistance, as well as the results Potentiodynamic polarization also confirms that the maximum harvesting rate is when the Lorentzian force is parallel to the surface. Based on the results, the magnetoelectropolishing method is suggested as an efficient method to improve the surface properties and corrosion resistance of stainless steel.

In the present study, Ti/SnO2-Sb/NSGCN-PbO2 electrode was fabricated by electrodeposition technique. The field emission scanning electron microscopy (FESEM) coupled to an energy dispersive X-ray (EDX) spectrometer, X-ray diffraction (XRD), linear scanning voltammetry (LSV), cyclic voltammetry (CV), chronopotentiometry (CP) and chronoamperometry (CA) analyzes were used to examine the surface morphology, the elemental composition analysis and electrochemical properties of the electrode. The findings showed that the Ti/SnO2-Sb/NSGCN-PbO2 electrode has a finer particles, a more compact and uniform structure, a higher potential for oxygen evolution, a smaller charge transfer resistance, a good current density and a more desirable electrode stability. In this study, the Ti/SnO2-Sb/NSGCN-PbO2 electrode performance in ciprofloxacin (CIP) removal was investigated. Electrochemical removal of CIP was done via anodic oxidation method by using generate hydroxyl radical (OH֯) on the anode surface. The removal efficiency of ciprofloxacin in 240 minutes at pH=6.8 and ambient temperature was 44.3%.Furthermore the amount of energy consumed was 0.368 kWh m-3. According to the obtained results Ti/SnO2-Sb/NSGCN-PbO2 anode performs better than Ti/SnO2-Sb/PbO2, Ti/PbO2 and Ti/SnO2-Sb in removing Ciprofloxacin and energy consumption.

In this research, the liquid-liquid equilibrium data of the ternary system (water + n-butyric acid + n-dodecane) were obtained at a temperature of 298.2 K and a pressure of 101.3 kPa. The ternary phase diagram was drawn using data of tie-lines obtained from acid-base and Karl Fischer titrations. Hand and Othmer-Tobias equations were used to check the correlation of data of tie-lines. The obtained fit coefficients (0.997 for both equations) showed that the tie-lines are reliable. The distribution coefficients and selectivity factors in the two-phase region were obtained in the ranges of 1.88 to 2.14 and 343.78 to 122.44, respectively. The values obtained for these two parameters showed that n-dodecane is a high-efficiency solvent for removing butyric acid from the aqueous phase. NRTL equation was used for thermodynamic modeling of experimental data. The obtained binary interactions were examined after validating the data. The quality of the modeling was evaluated by calculating the root mean square deviations (rmsd). The value obtained for it (1.11%) showed that the modeling was done well.

In the present investigation, a new series of mononuclear oxime palladacycles based on phosphorus ylides with the empirical formula [Pd{N,N'-C5H4{C(H)=NO}-2}(Ph2PCH2PPh2C(H)C(O)C6H4X)]ClO4 (X = Cl (1), Br (2), NO2(3) and OCH3 (4)) were synthesized. These complexes were formed through a cleavage chloro-bridges reaction of the dinuclear palladacycle complex in the presence of phosphorous ligands using sodium perchlorate and dichloromethane solvent. The synthesized complexes were characterized by elemental analysis, 31P NMR, 1H NMR, 13C NMR, and FT-IR spectroscopic methods. The obtained results of NMR and IR spectroscopes confirmed the synthesis of new mononuclear palladacycle complexes and the P,C-coordination mode connection for asymmetric phosphorus ylides. In addition, the catalytic activity of the synthesized complexes in the carbon-carbon coupling reaction and cytotoxic effect on A549, HT-29, and 1321N1 cell lines using the MTT-assay method. The results of this research can be promising for the use of these compounds as catalysts in the Suzuki–Miyaura carbon-carbon coupling reaction and anticancer agents.

In this research, a benzothiadiazole-based covalent organic framework (BT-COF) has been prepared through imine linkage and acid-catalyzed Schiff-base reaction, which has high crystallinity and chemical stability. The construction and application of a modified carbon paste electrode (CPE) with BT-COF nanoparticles as a voltammetric sensor (BT-COF/CPE) to measure silver ion is the basis of this research work. The obtained experimental data were properly fitted in a quadratic model obtained from the half fraction central composite design (HF-CCD) method. The main role of BT-COF in this voltammetric sensor can be related to the presence of multiple binding sites in its structure to form a complex with silver, large surface area and high volume of BT-COF pores which is known to weaken the steric hindrance when forming a complex between silver and COF binding sites, and also make it easier for silver to reach the functional groups inside COF channels, and in addition, they create a large space for the deposition of a large amount of silver. Regression at a significance level of 5% and in the range of 0.1-100 nM led to a linear equation between the stripping current and the silver ion concentration in the pre-concentration solution. The detection limit was 0.06 nM. The impact of interferences on the performance of the proposed sensor was investigated. Electrochemical and SEM/EDS/MAP methods were used to check the performance principles of the resulting voltammetric sensor. The ability of the prepared sensor to determine the amount of silver in real samples was investigated.

In this study, the oxidation of benzyl alcohols to aldehydes using nitrogen-doped mesoporous carbon spheres as a heterogeneous catalyst was investigated for the first time. Initially, Stöber method was used to synthesize silicate-polyaminophenol-formaldehyde structures using tetraethyl orthosilicate, 3-aminophenol, and ethylene diamine as silica templates, carbon precursors, and regulators, respectively, in an aqueous-ethanol medium with ammonia as a catalyst. The synthesized structure transformed into N-doped carbon-silica structure during annealing under inert gas. N-doped mesoporous carbon spheres were formed after etching the silica network with sodium hydroxide. The amount of nitrogen loading was determined by elemental analysis, and its amount was determined to be 8.00 wt%. The surface area determined by nitrogen absorption and desorption analysis is 1186 m2g-1. Based on FE-SEM images, the average particle size is about 300 nm. Aqueous benzyl alcohol oxidation was carried out using the synthesized catalyst to investigate its catalytic activity. A study has been conducted to assess the effects of temperature, time, oxidant type, and catalyst amount on reaction yield as well as catalyst recycling potential. The synthesized catalyst shows remarkable catalytic performance for benzyl alcohol oxidation, achieving high yield (over 88% within 6 h) and selectivity (99%). The catalytic activity did not change significantly after four recycling cycles.

A solid phase microextraction method coupled with ion mobility spectrometry (IMS) was employed as a simple and rapid approach for the determination of the hexaflumuron insecticide. In this method, nickel ferrite magnetic nanoparticles were used as adsorbent and dichloromethane was used as desorption solvent. In this method, after the end of the extraction steps and centrifugation, the desorption solvent containing the analyte was injected into the IMS instrument for analysis. The effects of various parameters including pH, type and volume of buffer, type and volume of desorption solvent, amount of adsorbent, and extraction time on this process were investigated. Under optimized conditions, the calibration curve is linear in the range of 1-150 ng mL-1 (R2=0.9998), and detection limit of the method was obtained 0.3 ng mL-1. The relative standard deviation (RSD) values (n=10) for concentrations of 10 and 100 ng mL-1 were found to be 1.4% and 3.4%, respectively. This method was applied as a suitable approach for the measurement of hexaflumuron in water, soil, tomato, fruit juice, and pistachio samples.

New complexes of nickel(II) and palladium(II) were synthesized using the ferrocenyl imine ligand. This Schiff base ligand was coordinated to the metal ions through the imine N and thiolic S atoms. The synthesized complexes were characterized by FT-IR, 1H NMR, UV–Vis spectroscopy and elemental analysis. The IR spectra of complexes show characteristic of imine group. Furthermore, the 1H NMR spectra display different protons of the cyclopentadienyl groups. The binding interactions of the compounds with DNA were investigated by the electronic absorption spectroscopy, and the intrinsic binding constants (Kb) were calculated for the Schiff base ligand, nickel and palladium complexes as 2.7×104, 1.2×105 and 7.2×104, respectively. The obtained data showed that the synthesized compounds bind to DNA via intercalative binding modes. Also, viscosity was investigated in order to further explore the nature of interactions between the compounds and DNA. Accordingly, it was found that the synthesized compounds bind to DNA via intercalative binding modes.

Melamine is a nitrogen-rich compound. Its composite with transition metals has an electron-rich structure and increases electrocatalytic activity and charge transfer. In this study, a copper-nickel melamine nanocomposite was prepared through a hydrothermal process and its electrocatalytic activity was investigated on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (GC/MWNT/MelCuNi) towards the oxidation reaction of methanol. (MOR). The stability of the synthesized catalyst was investigated by chronoamperometry (CA) technique. The surface morphology of the modified electrode was characterized by field emission scanning electron microscopy (FESEM) and the structure of the catalyst was determined by X-ray diffraction (XRD) patterns. The resulting MelCuNi nanocomposite has a higher current density (92 mA. Cm-2) and significantly better stability for the electrocatalytic oxidation of methanol. The effect of nickel and copper nanoparticles on the electrocatalytic performance of the synthesized nanocomposite in the presence and absence of melamine compared to MOR was also investigated.

Li-ion battery additives improve the performance, lifetime, and stability of Li-ion batteries by stabilizing electrode-electrolyte interfaces, improving electrolyte properties, facilitating efficient use of resources, and facilitating rapid lithium migration. However, fire safety, long service life, and capacity maintenance are all critical concerns for commercial Li-ion batteries. Several approaches have been explored to improve electrochemical performance, increase safety, and higher lifetime. Additives are one promising way to meet the above requirements. In this paper, we used dopamine as a cheap and safe additive (compared to organic compounds) at a concentration of 0.05 wt% to the electrolyte in a lithium-ion full-cell battery with a graphite anode LFP cathode (cylindrical battery 38120). Our results showed increased thermal stability, accelerated solid electrolyte interphase formation in graphite, improved CEI on the LFP cathode surface, and maintained 100% capacity after 200 cycles. This additive plays a constructive role in the LFP cathode to increase the performance of the Li-ion battery without causing combustion or environmental hazards.

Since the thermodynamic properties of liquid mixtures provide valuable data for the accurate and proper design of industrial processes and provide a desirable perspective on understanding the nature of intermolecular interactions between materials, they are of particular importance. In this study, the density and viscosity of binary mixtures containing cyclopentanone + 1-propanol to 1-hexanol at different temperatures (293.15, 303.15, 313.15, and 323.15 K) were measured, and the excess molar volumes (V_m^E) of the mixtures were calculated using the density values. Negative V_m^E values were obtained for the cyclopentanone + 1-propanol and 1-butanol mixtures only at 293.15 K, and positive values for the cyclopentanone + 1-propanol to 1-hexanol solutions were obtained at all temperatures. Additionally, the viscosity deviations (Δη) for cyclopentanone + 1-propanol to 1-hexanol were negative at all temperatures. The results indicate that the molecular interactions in solutions containing short-chain alcohols are stronger, while the increase in the hydrocarbon chain length of the alcohol leads to a weakening of the intermolecular forces. Furthermore, computational studies were used to investigate the formation of hydrogen bonds and their strength based on the values of hydrogen bond interaction energy (E), structural characteristics of the hydrogen bond length (R(O...H)), NMR spectroscopic data (O-H), and the values of electron density at the critical point of the hydrogen bond (BCP). The experimental excess molar volumes were compared with the computational data in the gas phase. All computational results confirm the decrease in the strength of the hydrogen bond between cyclopentanone and 1-alkanols with the increase in the alkyl chain length.

Urban wastewater is characterized by microbial contamination and a substantial quantity of suspended solids. Many existing municipal treatment facilities are unable to adequately process these wastewaters, resulting in only partial removal of pollutants. Implementing an effective method for the comprehensive treatment of wastewater from urban facilities for industrial applications is a viable solution to conserve water resources. This study employed a combination of coagulation and membrane filtration processes to treat the wastewater from Sahand town, with coagulation serving as a preliminary treatment and membrane filtration as the final treatment stage. Polyaluminum chloride and polyacrylamide were utilized as coagulants during the coagulation phase, while a microporous membrane was employed in the filtration phase. The findings indicated that the turbidity of the town's wastewater decreased from 129 NTU to 0.7 NTU following the hybrid treatment process, and the microbial load was entirely eliminated. Although there was a reduction in membrane flux, direct washing restored the performance, increasing the flux back to the initial value of 1500 L.m-2.h-1. The significant reduction in turbidity and microbial load to acceptable levels, coupled with the stability of membrane performance, suggests that the combined treatment approach is an effective method for treating urban wastewater for industrial use and for mitigating water wastage.

Coordination polymers (CPs) are synthesized using bridging organic ligands and metal ions, depending on the geometric coordination of the metal, the bridging ligands, and the donor atoms present in these ligands, various one-, two-, or three-dimensional polymeric structures can form. To investigate the effect of the position of the pyridine nitrogen atom in the tridentate NN'O Schiff base ligand on the type of coordination polymers, two copper complexes were prepared. The ligand HL2 was characterized using IR, NMR, and elemental analysis, while the complexes were analyzed and identified using IR, elemental analysis, and X-ray diffraction techniques. The structural data of the copper complexes indicated that changing the pyridine nitrogen from position 3 to position 4 in the Schiff base ligand altered the structure of the copper complex from two-dimensional to three-dimensional. Analysis of inter- and intramolecular interactions using the NCI program shows that the interactions in both molecules are of the hydrogen bonding, halogen bonding, CH…π, π…π stacking, metal…π, and lone-pair…π type.

In this research, for the first time, Bi/CeVO4/Cu4O3 nanocomposite was synthesized through a one-step hydrothermal method using hydrazine as both hydroxide ion production agent and reducing agent to produce bismuth metal. XRD, EDS, DRS, and FESEM analyzes were used to characterize the product. According to the analysis results, cerium vanadate and copper oxide nanostructures were formed on bismuth microstructures. Then, the photocatalytic performance of the as-synthesized products in the desulfurization of dibenzothiophene was evaluated under visible light irradiation for one hour. The desulfurization efficiency for the as-synthesized nanocomposite under visible light irradiation for one hour was about 88%, which is a favorable result. Also, by using Bi/CeVO4 nanocomposite, a desulfurization value of 75% was obtained, which shows the effect of copper on the ability of nanocomposite. In fact, Cu4O3 significantly improves the photocatalytic efficiency of Bi/CeVO4 by increasing the amount of light absorption, synergy in electron-hole production, and reducing the recombination rate.

In this study, graphene oxide (GO) was functionalized by sodium triphosphate (NaTPP) through a physical grafting method and used as a nanofiller to fabricate cation exchange membranes based on polyvinylidene fluoride (PVDF). The influences of the loading percentage of NaTPP in functionalized GO (GON) samples on the hydrophilicity, surface and cross-sectional morphology, permselectivity, and ion transport number of the sodium ion on the fabricated CEMs were explored using different techniques. Adding NaTPP to GO resulted in a more even surface structure, enhanced surface wettability, and decrement of membrane area resistance for the GON-based CEMs compared to GO-containing membranes. The MGON (0.5) membrane showed a high water uptake of 46.2 ± 2.3% and an ion exchange capacity of 3.8 ± 0.1 meq g-1, which facilitated the easier transport of monovalent and divalent ions within the membrane. The results showed that the MGON (0.5) membranes possessed higher permselectivity for monovalent and divalent ions including Na+ (98.3%), K+ (96.4%), Ca2+ (80.2%), and Mg2+(76.3%). Additionally, the membrane area resistance of this optimized membrane was 1.3 ± 0.2 Ω cm2, which was about 87.48% lower than the membrane containing unmodified GO.

The aim of this study is to remove the non-steroidal anti-inflammatory drug naproxen from aqueous solutions using a polyethersulfone (PES)-based thin film composite (TFC) membrane. This nanofiltration membrane was fabricated using the interfacial polymerization (IP) method and by forming an active polyamide layer on the microporous substrate surface. The morphology, roughness, and surface charge of the synthesized composite membrane were investigated using the field emission scanning electron microscope (FESEM), atomic force microscopy (AFM), and zeta potential, respectively. To evaluate the performance of the fabricated nanofiltration membrane, the rejection rate of monovalent and divalent salts of NaCl, Na2SO4, MgCl2 and MgSO4 was measured. The obtained results showed that the rejection rate of salts containing divalent sulfate anion, Na2SO4 and MgSO4, at the operating pressure of 4 bar is equal to 90.5% and 61.8%, respectively. The result of this research can create a broad perspective regarding the use of thin film composite membranes in the removal of naproxen as a hydrophobic drug from aqueous solutions.